Silo breather bag

ABSTRACT

A breather bag for use in a hermetically sealed silo to minimize silo pressure changes due to temperature variations is disclosed. The toroidal breather bag includes an air tube extending through the silo wall to establish air communication between the breather bag and the outside atmosphere. The toroidal bag is comprised of two arcuate tubular sections, each of which facilitates the use of only two sealed together sheets to form a half toroidal section. When laid flat before final assembly, top and bottom sheets each have ends including serrated edges defining 2-sided and 3-sided projections therein. On assembly, arcuate edges of the two sheets are sealed together, leaving the two ends each having a plurality of projections around its circumference. Adjacent projections are sealed together along their adjacent edges. Several of the sealed edges define staggered noncoextensive lines so that the sealed edges do not all come together at one central point. Thus, not more than three projections are contiguous to any one point.

United States Patent [:9

Hickle et al.

[ June 10, 1975 1 1 SILO BREATHER BAG [73] Assignee: R. L. Kuss & Co., Inc., Findlay,

Ohio

[22] Filed: Jan. 28, 1974 [21] Appl. No.: 436,906

[52] US. Cl 150/]; 99/646 S; 220/85 B [5 l] Int. Cl A4Sc 9/00; B65b 3/00; B65d 25/02 [58] Field of Search 220/85 B; 150/5, 1;

Primary Examiner-George E. Lowrance Attorney, Agent, or Firm-Vincent L. Barker, Jr.; Thomas M. Freiburger; Owen & Owen Co.

[57] ABSTRACT A breather bag for use in a hermetically sealed silo to minimize silo pressure changes due to temperature variations is disclosed. The toroidal breather bag includes an air tube extending through the silo wall to establish air communication between the breather bag and the outside atmosphere. The toroidal bag is comprised of two arcuate tubular sections, each of which facilitates the use of only two sealed together sheets to form'a half toroidal section. When laid flat before final assembly, top and bottom sheets each have ends including serrated edges defining 2-sided and 3-sided projections therein. On assembly, arcuate edges of the two sheets are sealed together, leaving the two ends each having a plurality of projections around its circumt'erence. Adjacent projections are sealed together along their adjacent edges. Several of the sealed edges define staggered noncoextensive lines so that the sealed edges do not all come together at one central point. Thus, not more than three projections are contiguous to any one point.

3 Claims, 9 Drawing Figures SILO BREATHER BAG BACKGROUND OF THE INVENTION The invention relates to hermetically-sealed silos, and more particularly to air breather bags for relieving internal pressure changes within such silos.

Inflatable silo breather bags, such as those manufac tured by A. O. Smith Harvestore Products, Inc., of Arlington Heights, III., are known in the farming industry. They are generally weiner-like in shape with usually two of them suspended in the silo near the top, so that the two breather bags approximate a broken toroidal or doughnut shape. The inflatable bags are open to the outside atmosphere but not to the inside air space of the silo, so that they exhale and inhale with changes in silo pressure. Rises in temperature cause the air and other gases inside the sealed silo to expand, thus increasing pressure. The silo breather bag gradually collapses as the pressure increases, thus preventing extreme pressure increases which could explode the silo. When pressure and temperature within the silo drop, the breather bag inhales air from the atmosphere filling up to absorb silo space. This prevents the development of extreme vacuums or negative pressures within the silo which could cause an implosion. The silo may thus remain sealed, keeping pressure changes at a minimum without admitting fresh air which would cause spoilage of the fodder within the silo.

Presently, silo breather bags are constructed from many separate sections. The body is made up of a number of sealed-together segments, each of which, in planar preassembly configuration. is an elongate, variably tapered sheet of material. Each segment is rolled to define a short cylindrical section of tapered cylinder height. The sections are annularly sealed together into an arcuate cylindrical shape, and a continuous elongate sealing strip is applied to retain each segment together at its juncture. The ends are circular pieces of material, peripherally sealed to the two end body segments. This construction requires a very great number of sealed seams, necessitating large expense in assembly and resulting in seam weaknesses and failures in later use.

SUMMARY OF THE INVENTION The present invention provides an essentially two piece silo breather bag construction with greatly reduced number and length of seams. Upper and lower arcuate planar sections having serrated ends with generally triangular projections therein are first separately curled together and their adjacent projection edges are sealed forming two halves of a weiner-like shell. The two sections are then put together and sealed around a continuous peripheral edge to form a hollow half toroid or closed weiner-like shell. A strong end construction on the arcuate breather bag results from the provision of a projection configuration which avoids contiguity of more than three projections at any one point. The present silo breather bag construction facilitates substantially reduced manufacturing expense and an improved, stronger seam construction.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional elevational view of a hermetically-sealed silo containing a breather bag according to the present invention, shown under conditions which cause inflation of the bag;

FIG. 2 is a partial sectional elevational view of the silo shown under conditions which cause deflation of the silo breather bag;

FIG. 3 is a plan view of the inflated silo breather bag;

FIG. 4 is a partially exploded plan view of a prior art silo breather bag, indicating the manner of construction thereof;

FIG. 5 is an end view of the prior art breather bag, indicating end construction;

FIG. 6 is an end view ofa silo breather bag according to this invention;

FIG. 7 is a plan view of a planar sheet of material for use as the top half of the present silo breather bag;

FIG. 8 is a plan view ofa planar sheet of material to be used as the bottom half of the silo breather bag; and

FIG. 9 is an elevational view of the assembled silo breather bag which constitutes one-half of the toroidal construction used in a silo.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings, FIG. 1 indicates a hermetically sealed farm silo 10 containing a quantity of fodder or other stored material 11 and having suspended near its top a pair of silo breather bags 12 according to the invention, one of which is indicated in the sectional view of FIG. I. The bag 12, preferably of thermoplastic material, has a plurality of loop tabs 13 which may be suspended from hooks 14 attached to the silo structure, as indicated in FIG. 1. Breather vents 16 connected to the breather bag 12 and passing through the silo roof 17 in a sealed connection provided the required air communication between the interior of the bag I2 and the outside atmosphere.

The pressure within the breather bag [2 is always equal to that of the outside atmosphere. When the pressure within the sealed silo 10 decreases due to a drop in air temperature outside and inside the silo 10, for example, greater pressure outside the silo 10 causes air to enter the breather vents l6 and increase the air content of the breather bag 12. This expands the breather bag 12, taking up additional space within the silo l0 and thus tending to cancel the negative pressure within the silo 10. It is possible, depending upon weather conditions when the silo 10 was sealed and upon extremes of temperature within the sealed period, that the breather bag 12 could be fully inflated without absorbing enough space within the silo 10 to eliminate negative pressure. However, the breather bag 12 effects a great enough volumetric change within the silo It] to prevent negative pressures of a magnitude which could cause implosion of the silo 10.

FIG. 2 indicates the silo I0 and breather bag 12 under conditions which cause exhalation of the breather bag 12. The usual condition is a rise in air temperature outside and thus inside the silo 10 on a warm day which effects a pressure rise within the sealed silo 10. When the pressure rises above that of the atmosphere, the bag 12 begins to exhale. As in the case with the inflating breather bag 12, it is possible for the bag 12 to be completely flattened without relinquishing enough silo space to absorb the pressure increase within the silo 10. However, the breather bag 12 effects a great enough volumetric change to prevent explosion of the silo I0.

FIG. 3 shows the silo breather bag I2 from above. Collars 18 of the loop tabs 13 are attached to the surface of the bag 12 preferably by heat sealing. Similarly, the breather vents 16 are heat sealed around openings 19 in the breather bag 12.

FIGS. 4 and indicate the manner of construction of a typical prior art breather bag 21. As FIG. 4 indicates, the construction of the bag 20 includes the use of many separate rolled body segments 21, requiring the sealing of a great number of annular seams 22. A continuous elongate sealing and hanging strip 23 seals each segment 21 together at its juncture 24, requiring a double seam along the entire length of the strip 23. A pair of end segments 25, sealed to adjacent sections 21, receive circular end pieces 26 in a circumferential seams 27. An arcuate form is thus generated by this multisegmented construction. The large number of seams 22 and 30 causes great expense in manufacture and seal ing problems in later use.

A breather bag construction according to the present invention is indicated in FIGS. 6, 7, 8 and 9. Top and bottom sections 28 and 29 are shown in planar configuration before assembly in FIGS. 7 and 8 respectively. Serrated edges with a plurality of twoand three-sided projections are provided in each end of the top section 28 and bottom section 29, the projections being numbered 31 through 42 in FIGS. 7 and 8. Each end of the bag is constructed generally in the manner shown in US. Pat. No. 2,673,024, which discloses a rectangular or multiple-sided open ended container with a flat end normal to the container walls. The terms two-sided" and "three-sided as used herein and in the appended claims to describe end projections are intended to include the generally twosided configuration of projections 33 and 37 and the generally three-sided configu ration of projections 36 and 40. These projections have been lopped off along the lines 53, 54, 55 and 56, respectively for ease of assembly. In this embodiment, each end of the assembled arcuate breather bag 12 comprises six such projections, as shown in FIG. 9. However, a lesser or greater number of projections may be provided. Fewer projections result in simpler end construction, but more projections will more closely approximate a circular end. Regardless of the number or projections, the construction indicated in FIGS. 7, 8 and 9 results in a completed breather bag comprised essentially of two sheets of material. The loops I3 and breather vents 16 are, of course, added before assembly of the bag 12.

The manner of construction of the breather bag 12 is as follows. Arcuate edges 44 and 45 of the top section 28 are first brought downward to roll the section 28 into a half-tubular configuration. The projections 31, 32 and 33 are then sealed together at adjacent edges. The projections 37, 38 and 39 are similarly sealed. The bottom section 29 is then rolled upward into a similar configuration with arcuate edges 46 and 47 curled upward and projections 34, and 36 and 40, 41 and 42 sealed in the same manner. All seams are preferably lap-sealed. Since the two-sided projections 32, 38, 35 and 41 are shorter than their neighboring projections 33, 37, 34 and 42, and since the three-sided projections 31, 39, 36 and are of the shorter length with truncated tips 31a, 39a, 36a and 40a, each end of the top and bottom sections 28 and 29, before the sections are assembled together, has one straight coextensive edge 51, as seen in FIGS. 6 and 9. The projections above and below these edges 51 form the staggered seam configuration shown in FIGS. 6 and 9.

Following the subassembly of each of the top and bottom sections 28 and 29, the sections 28 and 29 are sealed together along the end edges 51 and along seams 57 formed by the outer arcuate edges 44 and 46 and the inner arcuate edges 45 and 47. If lap sealing is used on all seams, the back-up of the final lap seam is provided through an opening at one of the breather vents 16. For clarity, FIG. 9 shows the assembled breather bag 12 as if inflated.

As indicated in FIG. 6, the construction described results in an end configuration having one coextensive seam 51 and several additional staggered seams 31/32, 32/33, 34/35, and 35/36 which do not come together in one common point. Thus, not more than three projections are contiguous to any one point, eliminating the occurrence of any weak point and resulting in a strong end construction.

The above described preferred embodiment provides a silo breather bag of essentially two-piece construction, with a strong end assembly and a greatly reduced number and length of seams as compared with the prior art. Various other embodiments and alterations to the above embodiment will be apparent to those skilled in the art and may be made without departing from the spirit and scope of the following claims.

What we claim is:

l. A tubular silo breather bag for use in a hermetical ly-sealed silo, comprising two sheets of material defining a top and a bottom, each sheet having a first arcuate edge, a second arcuate edge of shorter arcuate length and sharper curvature than said first edge, and two ends having serrated edges defining, at each end of the breather bag, pairs of opposed two and three sided projections, said two sheets being sealed together at corre' sponding arcuate edges and at adjacent edges of adja' cent projections with the projections converging generally centrally at each end of said joined sheets, the projections in each pair being similar with at least one projection of a different shape located therebetween, one pair of projections being of length sufficient to form an overlapping sealed portion of corresponding opposed edges of the pair, the remaining sealed edges defining staggered noncoextensive lines, all of said projections when in sealed relationship forming a generally polygonal end with not more than three projections being contiguous to any one point, said assembled sheets forming an arcuate weiner-like inflatable bag, said bag having an air duct extending from one of said two sheets for connection to an opening in the silo.

2. An arcuate inflatable silo breather bag construction, comprising a top sheet and a bottom sheet of flexible material, each having, in planar preassembly con figuration, an outer curved edge and an inner curved edge of shorter curve length and sharper curvature than said outer edge, and two ends having serrated edges defining projections therein, said two sheets being sealed together at corresponding arcuate edges and at adjacent edges of adjacent projections, said serrated edges, at each end of the assembled breather bag, defining pairs of opposed two and three sided projections converging generally centrally at each end of the joined sheets, the projections of each pair being similar with at least one projection of a different shape located therebetween, one pair of projections being of length sufficient to form an overlapping sealed portion of corresponding opposed edges of the pair, the remaining sealed edges defining staggered noncoextensive lines,

3,888,288 6 all of said projections when in sealed relationship form- 3. The silo breather bag of claim 2 wherein said poing a generally polygonal end with not more than three lygonal end is generally hexagonal with six projections projections being contiguous to any one point, said therein.

joined sheets forming an arcuate tubular bag. 

1. A tubular silo breather bag for use in a hermetically-sealed silo, comprising two sheets of material defining a top and a bottom, each sheet having a first arcuate edge, a second arcuate edge of shorter arcuate length and sharper curvature than said first edge, and two ends having serrated edges defining, at each end of the breather bag, pairs of opposed two and three sided projections, said two sheets being sealed together at corresponding arcuate edges and at adjacent edges of adjacent projections with the projections converging generally centrally at each end of said joined sheets, the projections in each pair being similar with at least one projection of a different shape located therebetween, one pair of projections being of length sufficient to form an overlapping sealed portion of corresponding opposed edges of the pair, the remaining sealed edges defining staggered noncoextensive lines, all of said projections when in sealed relationship forming a generally polygonal end with not more than three projections being contiguous to any one point, said assembled sheets forming an arcuate weiner-like inflatable bag, said bag having an air duct extending from one of said two sheets for connection to an opening in the silo.
 2. An arcuate inflatable silo breather bag construction, comprising a top sheet and a bottom sheet of flexible material, each having, in planar preassembly configuration, an outer curved edge and an inner curved edge of shorter curve length and sharper curvature than said outer edge, and two ends having serrated edges defining projections therein, said two sheets being sealed together at corresponding arcuate edges and at adjacent edges of adjacent projections, said serrated edges, at each end of the assembled breather bag, defining pairs of opposed two and three sided projections converging generally centrally at each end of the joined sheets, the projections of each pair being similar with at least one projection of a different shape located therebetween, one pair of projections being of length sufficient to form an overlapping sealed portion of corresponding opposed edges of the pair, the remaining sealed edges defining staggered noncoextensive lines, all of said projections when in sealed relationship forming a generally polygonal end with not more than three projections being contiguous to any one point, said joined sheets forming an arcuate tubular bag.
 3. The silo breather bag of claim 2 wherein said polygonal end is generally hexagonal with six projections therein. 